Simplify the following expression: $a = \dfrac{6x}{9} \div \dfrac{2x}{7}$
Explanation: Dividing by an expression is the same as multiplying by its inverse. $a = \dfrac{6x}{9} \times \dfrac{7}{2x}$ When multiplying fractions, we multiply the numerators and the denominators. $a = \dfrac{ 6x \times 7 } { 9 \times 2x}$ $a = \dfrac{42x}{18x}$ Simplify: $a = \dfrac{7}{3}$